In order to meet the growing demands of the modern clinical laboratory to provide cost effective services, the use of automated clinical analyzers has increased. Reliance on automated clinical analyzers improves the efficiency of the laboratory procedures inasmuch as the technician has fewer tasks to performed. Automated clinical analyzers provide results much more rapidly while frequently avoiding operator or technician error, thus placing emphasis on accuracy and repeatability of a variety of tests.
Generally, analysis of a test sample involves the reaction of test samples with one or more reagents with respect to one or more analytes wherein it is frequently desired that the analysis be performed on a selective basis with respect to each test sample. Typically, such analysis involves forming a reaction mixture comprising the test sample and one or more assay reagents, and the reaction mixture is then analyzed by an apparatus as described above for one or more characteristics of the test sample.
Automated clinical analyzers are presently available for automatically performing such analyses of a test sample. Such analyzers typically include transport systems such as conveyor systems and carousels designed to transport containers of sample liquids between various operating stations. For example, a reaction tube or cuvette containing a test sample may pass through a reagent filling station, mixing station, reaction forming station, detection stations, analysis stations, and the like. In particular, various automated immunoassay analyzers have been provided such as the Abbott IMx.RTM. analyzer and the Abbott TDx.RTM. analyzer (Abbott Laboratories, Abbott Park, Ill., USA), often referred to as batch analyzers, which utilize procedures involving a variety of different assay steps which typically rely on detection and measurement of optical changes in a reaction mixture during the assay process. Random access analyzers have also been described which not only can analyze multiple test samples, but multiple analytes may be analyzed from each test sample. In addition, presently available sequential and random access analyzers include various reagents within the apparatus itself or placed near the apparatus for pipetting purposes. Liquid reagents, in bulk form, are selected for the various types of tests which are to be performed on the test sample, and are stored in or near the apparatus. The reagent delivery units, such as pumps and the like, along with valves, control and pipette mechanisms, are included in these automated analyzers so that different reagents can be mixed according to the type of test to be performed. Recently, apparatus and methods have been proposed for performing, selectively on the same sample, various homogeneous and heterogeneous assays concurrently in a random access fashion. Such apparatus and methods provide for the analysis of a plurality of liquid samples wherein each sample is analyzed with respect to at least one analyte utilizing both homogeneous and heterogeneous assay techniques.
Typically, such automated analyzers include assay reagent packs or containers from which assay reagents contained therein are removed during operation of the analyzer in order to carry out a particular analysis. Alternatively, a technician may be required to remove such assay reagents from a container not associated with the analyzer for introduction thereof into the analyzer. In many instances, such assay reagents comprise one or more components which must be substantially homogeneous upon removal from the reagent container or pack in order to provide consistently accurate and reliable results when used for performing a particular assay. Since such assay reagents must be stored in assay reagent containers or packs for accessibility by a technician or the automated analyzer for extended periods of time, they tend to lack uniformity or homogeneity as a result of, for example, settling of assay reagent components, such as the settling of microparticles in an assay reagent for use in a heterogeneous immunoassay as described above.
In order to maintain homogeneity of such assay reagents, removal of the assay reagent container or pack and manual manipulation thereof by the operator, such as by inversion or agitation of the assay reagent container or pack, is required. Where the analysis of a test sample employing such assay reagents or portion thereof is performed manually, such as the addition of assay reagents prior to introduction into an automated analyzer, manual manipulation of an assay reagent container or pack by a technician is also nevertheless needed. In either instance, such manual manipulation is time consuming and cumbersome, and can lead to operator error, loss of assay reagents, and, when removal of an assay reagent container or pack from an automated analyzer is required, could result in damage to the automated analyzer. In addition, manual manipulation of an assay reagent container typically causes foaming and bubbles which result in inaccurate pipetting.